This circuit was found in a Popular Electronics from the 90s. It is based on components still common today and an optical coupler for the triac. The sensor is a thermistor.
This circuit is from a 1968 documentation using one of the first integrated circuits available at the...
Using an optocoupler this circuit turns on the light in a bedroom for a set amount of time when...
This circuit was found in an old publication from 1971. A 741 can be used in place of the original...